


Was it really that bad?

by mischievousandplayfulV



Category: Undertale (Video Game)
Genre: Alternate Universe - Swapfell, Collars, Dom Papyrus, Ecto-Penis (Undertale), Ecto-Tongue (Undertale), Ecto-Vagina (Undertale), Fontcest, Leashes, Light Bondage, M/M, Master/Pet, Mating Cycles/In Heat, My First Smut, Smut, Sub Sans, Watersports
Language: English
Status: Completed
Published: 2016-09-25
Updated: 2016-09-25
Packaged: 2018-08-17 07:21:54
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,756
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8135248
Author URL: https://archiveofourown.org/users/mischievousandplayfulV/pseuds/mischievousandplayfulV
Summary: After being filled to the brim, Sans shows a certain side that he would have never showed before. Papyrus feels instant regret as Sans starts to desert himself from him. What he didn't know was that it was for another reason. Heats affects your mind more than you would think, Sans' heat is screaming for his brother's touch. Was that event really that bad?
 
(I'm so bad at summaries.)





	

**Author's Note:**

> This fic was inspired by eli-sin-g's beautiful art, if you haven't checked her out please do.  
> The comic can be found at http://eli-sin-g.tumblr.com/post/149738410303/i-never-thought-id-have-a-piss-kink-but-well  
> First fanfic I've ever done or uploaded, and it was smut of course.  
> First time writing smut so if it's not that good now you know why.  
> Sorry if the chaaracters are a bit off from what they are supposed to be.  
> I'm such a sucker for fontcest and the swapfell universe, hahaha.  
> Swapfell nor the characters are made by me.

It had been a week since that disgusting event, but that didn’t stop Sans from wanting to repeat it. He had deserted himself after that happened because that imbecile of a brother got an apology from him. After a while he just accepted the fact that he liked it, heh, he loved it. Now, himself entering a heat wasn’t helping in a bit, he wanted to be filled to the brim with Papyrus’ sweets. So a plan was in his works, one that would give him full control of whatever was going to happen.

…

~Last week:~

“Ahh, s-sto” 

That was the only thing that Papyrus could remember before realizing the mistake he just made, it involving his more than cum surprise. He could just recall himself being done with his lord’s petty disrespect. Not only was he treated as a dog, but also as a slave and lover. He worked for his lord’s needs, mutt was he, he would show him mutt.

“How’s that for a dog, huh?”

What happened after that event was quite unanticipated, accidental, even stunning if someone asked him. His lord, the most notorious assassin, the captain of the ever feared royal guard, was begging for him to keep going. Not only that, but his eyes had shifted into massive blue hearts and he had called him Pappy, the feared slayer, was blushing like mad. All of his cute little moans was filling the room, Papyrus felt like he was in heaven, he wanted more, but he knew that if he advanced he might get in some deep punishments that not even someone like him would enjoy. Papyrus just stared not knowing what to do, that was until he felt his soul turn to blue, he started to rise and felt getting thrown into the hallway. Behind him he felt the door close abruptly.

“I must have read the situation wrong, only someone as vile as me would enjoy something like that.”

Papyrus picked his stuff up and got to the bathroom to clean himself up, after this he would totally go to Muffet’s for a well deserved drink, it may be his last for all that he knew.

“That idiot, I told him to stop, I hated every single part if it.”

After he heard his Papyrus leave from the bath, he entered it as well.  
“I’m so foolish, not only did I let that moron see me like that, I also apologized, uhhh, that’s why I hate when his animalistic side takes the control.”

As much as Sans would like to say otherwise, he totally loved it and felt empty when Papyrus stopped moving. After he got out of the bath he went to make dinner for himself and decided to take a nap. He would never let that revolting dog ever get that close to him again.

…

 

As one would only guess, Papyrus was out cold in the bar after one too many drinks, after a while you would think he would learn or something. Muffet ended up grabbing him and flinging him out of the bar, she wasn't going to take care of a drunken child, but she did hope he wouldn't perish though, he was her most frequent costumer. After a while, the feeling of getting frozen woke Paps up, it was starting to sting. He, by some miracle, got home and went to the sofa, then he passed out again. 

…

Sans woke up, as always, early to start his early routine. He took a nice, heated bath, got dressed and moved to the kitchen. There he made his breakfast and ate it in peace, after the plates were done washing he went to wake his brother up, if he could be called that. 

“Papyrus, you bonehead, wake up this instant before I dust you.”

He smirked at that pun, he may have a deep objection towards jokes, but he enjoyed one or two, specially from himself.

“Mmm, coming milord, ugh my head.”

Papyrus got up as fast possible, even if it was very tough to do so thanks to his headache, he never learns. He grabbed his head as he got up to get some painkillers from the top drawer. The site could almost be laughable if it wasn't for Sans wanting to leave. 

“What an idiot.”

He whispered to himself, even though Paps could clearly hear him. After that Sans grabbed his leash and added it to his mutt’s collar. Papyrus has to remember who he belongs too, if you saw them, you would clearly think that nothing had happened between them. Papyrus was already used to the morning walk to his station, the embarrassment not even there.

…

It had been a week since that affair and Sans had only been deserting himself more, Papyrus was getting worried about this sudden change. Had him filling him up actually left such a mark on him? Papyrus had apologized so many times to his lord that not even Sans could hear it one more time. In Paps mind, he thought that Sans was so disgusted with his actions that he didn't even resist seeing him. What he didn't know was that that was even farther from the truth. 

…

He couldn't believe what he was debating about right now, at some point he decided to do it a certain way, one could say even fun. How much debate could one give when their body was screaming for the touch of his lover, heh, the feeling of getting filled harshly. It would take some time to be able to fool Papyrus into doing it over again. That idiot hadn’t stopped apologizing after what happened between them and it was getting on his nerves. Maybe it would be easier taken that his pet had been seeking his company for a while, his lord would show him how much he appreciated every part of him. The first step to follow is to plan every single moment, you know, to reign over the situation. Gosh, this heat was really getting the best of him, a glass of water should satisfy his needs until he finishes planning everything out.

…

Papyrus was very worried about his brother since he saw him this morning, his lord had not attended his job and stayed home. With every passing moment in his station, he couldn't stop thinking about him. He looked feverish and warm, also he had a big blue blush surrounding his bones. He looked like a cute, adorable, sexy blackberry, if Sans ever heard him say that he probably would die before letting out a chuckle. After his shift was done, he went to the nearest shop to get some more painkillers, ice and some candy. Painkillers were mostly for his night outs at Muffets, the ice for his lord’s fever and the candy just to smooth his temper. Something that Papyrus found out was that a weakness of Sans was the sweet, his lord loved sweets, but would never admit it. He used candy mostly when his lord wouldn't talk to him for any reason, he would leave it in certain places and that improved his temper pretty easily, even if he tried to hide it. He had to be careful though, too much would make Sans go in a sugar crash, that was never pleasant. After getting what he wanted, he took a shortcut to the front of his house, Sans hated it when Papyrus appeared out of nowhere in the house, he opened the door and got inside.  
When Papyrus came home, Sans sensed his arrival, that type of magic is very easy to track, he probably used a shortcut for it to be this powerful. He wasn't the most feared creature in the underground for nothing, also, the heat brought his senses to full power. Right now his senses told him that he wanted to get wrecked by his lover’s member. His heat was making him into such a slut, so against his dominating nature. Thank goodness that he had prepared everything in the morning, after he checked everything, he fixed his clothes, put water on his face to lower the heat, which didn't work, tried to put his normal face and went straight down.

... 

After he finished putting away the things that he bought he heard some footsteps behind him, he froze and started to shake. Slowly he spun himself around and saw Sans in his normal ware, in other words, he didn't have the armor. He gave him a nervous smile and started talking.

“Hey milord, are you ok? You didn't go to work today.”

His lord was just standing there with a slight smirk.

“I’m perfectly fine Papyrus, I just decided to take a break, work has gotten a little, stressful. Those idiots should work perfectly without me for a day, if not, well, you know what happens.”

His lord never takes breaks, that made him incredibly confused, but maybe it was true. 

“If you need anything from me milord, I’ll be up in my room.”

Paps was about to head for the stairs before a hand grabbed his coat rather harshly.

“Actually, Pappy, I was thinking that maybe you would like to play a simple game that I found.”

That tone of voice, it was almost, dare he say, flirtatious, maybe Sans was actually very sick, and Pappy too, what did he want from him now?

“What is this game that you are suggesting milord?”

For a second he could have swore that he saw something change in his lord’s eyes.

“You see dear brother, I have a small challenge for you, I would like you to be able to complete it without any problems.”

“I will do whatever you ask of me, milord. What shall I do to give you the results that you desire?”

His nice pet, always willing to do whatever needed to impress or finish whatever task was thrown at him. Papyrus was falling for his plan like if it was the most normal thing to do, he wouldn't delay this any further, the heat was getting the best of him.

“Now, mutt, follow me upstairs.”

When Papyrus heard that word, a certain, familiar fury rang from inside him. But he wouldn't let such a simple word destroy the fact that is lord finally wanted to spend time with him. Even if it may not be the best thing for him.

“Yes milord, I’m right behind you.”

As they got to the top floor, they headed to Sans’ room and opened the door, when Papyrus entered the room, he felt a shiver going through his spine. He barely even got to be inside his lord’s room, it was more for their “play dates” than anything else. Entering in the room is like entering a whole new world, it looked nothing like their house, it was spotless. The thing that first got his attention was the binds over the bed, he got a mixture of anxiousness and lust at the sight. Was he going to get punished? Was the reason that Sans wouldn’t talk to him was because he was planning a good lesson for him to learn? He looked down and waited for further instructions.

“The rules are pretty simple, even someone like you could follow it.”

Sans lead him to bed and gestured him to sit. Sans started taking of his signature coat and took it to hang it in his closet, after he had accomplished just that, he started binding his hands to the bed frame. How weird, he wouldn’t be able to touch or grab anything, what was even weirder was that that was the only thing that was tied. He didn’t dare to speak, scared that he might get a harder punishment for it. As his lord finished with his work, he gave a satisfied smirk and looked him right in the eyes.

“Tongue-tied I see. Well I won’t make you wait much longer. The game is simple if you follow the rules correctly. I will give a decent amount of water every 20 minutes, you will hold whatever necessity needed for as long as possible. You must at least last a few hours before you break.”  
So, what his lord wanted was to do some watersports? He didn’t expect this encounter to be even remotely close to sexual or kinky. Where did his lord even get this ideas? He probably should get rid of the internet connection, that’s the only place he could expect for him to learn this. He probably shouldn’t have drank as much as he did when he was out shopping, this was probably going to be painful and, somewhat thrilling, he seriously was a sick person. He got somewhat comfortable and looked right to his lord.

“Yes milord, I understand, how will I drink though, my hands are a bit tied at the moment”

“That’s no problem, I will come to this room every 20 minutes and give you the water myself, then I’ll go to continue with my day, if, at any moment you feel like you’re done, call me immediately.”

Sans then gave him the first half a liter of water, starting strong he sees. At the close proximity, he could see Sans’s bones resonating with a faint blue, especially his face, he would be lying if he said that he couldn’t feel his own arousal in his face at the proximity, After he finished it, Sans left the room and worked on whatever was needed. That would leave some time for Papyrus to administer what was happening right now.

…

His brother was more talented at this than he thought, he had gone to his room and back for about two hours. He wasn’t holding out his heat as well though, everything was becoming foggier, but he had to keep it all together. For that to happen, he was found most of this time playing with himself, but he never got to climax, he always hold back. He had great control over his loudness, even though it was getting hard to keep a straight face, yes he played with himself in his brother’s pathetic excuse of a room. 

…

It had been a while since they started this game and Papyrus still couldn’t figure out what was happening. He had to complete this challenge, that was clear, but, why was his brother blushing so much. After another dose of water, he started noticing how his lord’s eyes would get disappointed at how he was holding. Wasn’t that exact thing what his lord wanted? It was getting hard to hold it in by now, but not enough to actually hurt or anything. After trying to place the puzzle pieces together, he got the idea that his head was trying to block. It all made sense, the blue blush all over Sans’s bones, the game, the deserting, the disappointing look, his brother was in a heat, a very lustful one indeed. Somehow, some time later after registering the information that he just got, he felt a growl come up. Heats are a very contagious thing, especially if it is headed right to you, he had come up with a small plan to give what his lord desired, but still playing the game. If an animalistic fuck was wanted, then that was what he was getting, the mutt does not play around. He would just wait for the next round of water to come.

…

“You’ve been holding out well my sweet pet.”

Said Sans as he entered the room, he had the water in one hand and climbed on the bed.

“Thanks milord, anything to please you.”

Somehow, Sans noticed the change of tone and stared at those eyes, those dominant eyes, but he ignored it.

“I would expect nothing more from you mutt, here have a drink.”

Sans took the drink to his brother’s teeth and then took it back, he then climbed out of bed and headed to the door.

“Milord, if I may, could I request something from you?”

“Depends on what it is, what is it?”

“As you see, I want to go for as long as possible, to please you and only you.”

He started saying, his voice going deeper as every word passed, that sight made Sans feel hot.

“But, to be able to do that, I would like to take the rest of my clothes off, for them not to be a bother for the activity.”

“If that’s what you would prefer brother, but after that you go back to the binds.”

Papyrus gave Sans an almost, too innocent, smile, then he nodded. Sans went back to the binds and started untying them very carefully. He prayed that his brother wouldn’t sense the heat radiating from his over sensitive bones. Afterwards he gave his lover some space to do what he needed. The show was quite intriguing, but it made him blush more than he would have favored to show. Papyrus did that on purpose though, he took his orange turtleneck slowly showing off his rather impressive bones, each with a scar that expressed a different story. Then he took his pants slowly, almost like tempting Sansy to break. He had his member standing tall and proud, for a while, Sans couldn’t take his eyes from that certain sight, heart eyes flickering for about a second. He then caught himself and looked somewhere else, that place being Papyrus’ face. 

“What’s wrong milord, something seems to be bothering you.”

Papyrus got closer and that making Sans lose their balance and he fell onto the bed, which Papyrus got into after.

“Does me being this dominant really turn you on that much.”

He said as he took Sans’s bandana from his neck bones and tied his lords hands together. His lord must have really been affected by the heat because if that wasn’t the case, he would probably had died before even getting this close.

“Look at your slutty, lustful face, just begging to be satisfied, well I aim to please, always had.”

Sans was lost, everything happened so fast, how did his brother even get the information about him being this desperate, and why was he letting him have his way? All those thoughts went blank when he felt some magic starting to generate from his brothers mouth, that tongue that he very much loved to taste was licking his sensitive clavicle and neck bones. 

“Ahhh-hh, pap-ppy.”

All those moans coming from Sans’ mouth was like hearing a choir of angels, it wasn’t everyday that Sans would be this opened. He kept his work up, he went from his lord’s clavicle to the jaw. The sounds were cascading like a waterfall. He decided to start kissing him.

“Nggg-hhh.”

Sans was pinned down by Paps’ legs and his arms by Papyrus’ free hand. The other was holding his jaw in place, Papyrus was not letting him go anywhere anytime soon, not like he wanted. Their tongues fought for dominance, in which Paps won, each other’s tongue would play against each other, savoring each and every passing moment. After a few minutes they broke up for air.  
“Grrr-rr, those soun-ds, are driving me insane, I need more Sansy.”

He started taking his lord’s shirt and threw it on the floor, then his brother’s pants went next until he was laying all the way naked on the bed. Much to Sans’ dismay, his entrance started to form from all this action, and it was already dripping, Papyrus dismissed it though.

“All these pretty bones, just for me, no one else's.”

He started praising every single bone, starting from the side of Sans’ skull, to his clavicle, to every rib in his chest, until reaching his phalanges. No scar went unattended, they shouldn’t be there in the first place, but they made his lord what he was today, a strong, sexy blackberry. But for Sans, this was more torture than anything else, his touches were teasing and they jumped the part where they needed them the most. He was a pile of moans and blush, nothing like anyone would expect from the captain of the royal guard. Something about being pinned and forced really turned him on.

“Paa-apss, I-I need.”

“Yes Sans.”

Answered Papyrus, stopping his only contact with pleasure, making him whine.

“What is it milord, I can’t possibly please you if you don’t tell me what you need.”

“I n-need mo-rree.” 

“Need more of what, please use your mouth Sansy.”

Now he was just being cruel, not that Sans himself would have done anything different.

“I-I need yo-ouu to fuuuck mee, fill me up.”

“I don’t think that you’re ready for that just yet though milord, let me get you prepared.”

He was going to argue until he felt himself get his tied arms hooked against a bone structure, then he felt Papyrus go lower, and lower until he got to where his touches were the most desired, but had been neglected for a while. He then managed to grab his lord’s legs to hold him in place. He then gave Sans a dominating, but smug look as he looked from the magic to his brother’s eyes, Sans returned a more lustful, heart eyed, look. Not so dominating now are you?

“Do you even deserve my kindness, milord. I should just act like the mutt that I am, fast and rough, not slow in the least.”

Sans was trying to raise his hips for his brother to actually start doing something, but, he was pinned. He wanted to beg, but, he was humiliated enough, he didn't need more. He started to pant hard, his breath getting hard to control.

“But maybe, that’s how you like it, why you like to anger me, for me to show my animalistic side. Isn’t that right, Sansy?.” 

Sans looked away, he was incredibly turned on by his dominating presence, but he wasn’t going to just say it. He was always in charge anyway, but this heat of his made him do other things.

“Sans, tell me that you want it, you want me to lick your dripping honey.”

He gave a sexy chuckle at that, especially as his lord’s face turned bluer, if that was possible. He could barely control himself, but he did, maybe Sans needed some convincing.

“If you don’t want to use your mouth to tell me, then I’ll use mine to make you talk.”

He then plunged right into Sans’ slit, looking back at him. He gave a long lick from the clit to the bottom. Then he thrusted his tongue on the inside, but only barely, if Sans wanted him to go further, he would have to beg. The flavour that he got from his lord was intoxicating, he couldn’t stop, neither Sans moans nor panting did neither.

As Sans’ mound was assaulted, he could feel his wall starting to shatter, his mind was swimming with desire that he just wanted to comply in anything that his brother told him. He tried his best to muffle his moans and sounds, but, it was pretty much impossible in the state that he was in. Papyrus hummed against the magic, feeling it tremble to his every touch then he got part of what he was looking for.

“Pap-py, so go-od, your tongue, so good. Ahhh-h.”

Sans gasp after he felt Papyrus change position, no, he was getting close, he needed the other’s member so badly.

“Pappy, I need you~”

Paps let out an amused chuckle as he placed his teeth over the other’s. He then started kissing him deeply again. Sans felt the tongue asking for permission, of course he would let him in. After a few minutes of passionate making out Paps was pretty much ready to take Sans over, that and he really needed to free the liquids from his cock. 

“Milord, I think that I’ve made you wait enough, and you put up with me so well. Are you ready, milord?”

Sans couldn’t talk thanks to his pretty much messed up mind, but he managed to simply nod. He felt Papyrus line up his cock to his ever waiting entrance. He tried to cling to something, to keep him grounded, but his hands being tide up made it impossible. He then gave a small yelp, a soundless scream as Papyrus entered a little bit.

“Already gasping? I’m not even half way in yet, aren’t you a slut for my cock?”

“I’m not a-a slut-t. Keep going~”

Sans managed to say, while trying to make his hip bones move in a way for the member to enter further.

“So naughty Sans, already begging for more, I will give you what you want, as I said, I aim to please.”

As he said that, he thrusted his cock all the way into Sans. Both Sans and Papyrus gasped in pleasure at the same time. Papyrus fell over Sans and started kissing him, Sans’ pussy was just squeezing him just right. It was wet and warm, just perfect, he just wanted to get straight into pounding his lord, but he wanted him to beg.

“Ahh~ yes Pappy, move Pappy move, I need it now.”

“Ok Sans, if you want it.”

He then started to plunge in and out at a normal speed, not to fast, not to slow, enough to satisfy for a bit. 

“Ahh-hh Pappy, yes, harder, harder!”

“Hmm?”  
He said like if he was thinking.

“Anything for my little blackberry.”

He then flipped Sans onto his stomach and started pounding. As you may guess, all control was gone from his hands. 

“Ahhh-hh~”

Sans let out a most pleasured scream as he got pounded into the bed. If his moans were before loud, he must be screaming right now.

“Grrrrr. Sans, don’t you know how much those sounds make me want to wreck you?”

Papyrus moved fast and hard, the bed frame was slamming into the wall, it was possible that they could end up breaking it. The only sounds that could be heard from their lovemaking was the bed slamming into the wall, the bone against bone clanking, Sans’s moans and Papyrus’ growls.

Papyrus then looked at Sans’s exposed and made a move to grab it. He then started pumping his spine while he licked Sans’ exposed back bones.

“Oh fucking stars Pappy. That’s too much, I don’t think I can take it.”

“Just hold on for a little while.”

Sans movements became erratic as he got closer to finishing, he went down to meet up with Papyrus’ movements. 

“Pappy I-I think I’m going to cumm~”

“Cum for me Sansy.”

As if hitting a button, Sans gave out a scream as he climaxed. Papyrus kept going, not missing a beat.

“Don’t worry milord, I’m getting closed.”

Sans was still gone from his orgasm, he was coming back though. Papyrus then made the bone structure disappear and he took the knot off his hands.

He flipped Sans over again and just stared at his heart eyes. He then smiled and put his head right in his brother’s clavicle.

“Ahh~ Pappy, I need you. Fill me up all the way.”

His movements lost pace as he got closer, getting sloppier. After a while he let everything out.

“Saanss~”

He moved through his orgasm and then he layed over Sans, his member disappearing.

“That felt really good Paps, let's do it again sometime, now,” 

Said Sans as he grabbed Paps by the collar.

“go clean me up.”

Papyrus just smiled at his lord and got his tongue to work.

…

It was morning and Papyrus woke up with his lower part hurting, he couldn’t feel his legs and he could hear his bones cracking. At his side was Sans laying there, staring at him with normal eyes, probably the heat was gone after yesterday’s intense event.

“Good morning milord, did you sleep alright?”

“I certainly did my pet, thanks for the help yesterday, but now...”

He then went and slapped Papyrus in the face.

“Remember that I’m in charge here, that was a once in awhile event, you won't mention it to anyone.” 

He then went and grabbed Papyrus’ face and kissed where he hit.

“But I did enjoy it immensely.”

Papyrus just smiled and returned the soft kiss. He then laid back again, until Sans threw him off bed.  
“Not lazing out Papyrus you have to go to work.”

“But milord, I can’t move.”

“That’s your fault for not exercising often with me.”

“Heh, I love you milord.”

“I do too, my sweet love.”

**Author's Note:**

> Thanks for reading ;)  
> Please comment if you have any suggestions to improve it or requests.  
> If you would like to make any fanart (why i don't know), please send it to me I would love to see it.


End file.
